Oil tank cleaning apparatus



Dec. 22, 1936. B. oLssoN 2,055,462

OIL TANK CLEANING APPARATUS 2 Filed Feb. 11, 1936 Z/TNESSES INVEMT OR Patented Dec. 22, i936 UNITED STATES PATENT OFFICE on. TANK: CLEANING APPARATUS L Bengt Olsson, Brooklyn, N. Y. Application February 11, 1936, Serial No. 63,300

' 4 Claims.

My invention relates to an improvement in tank cleaning methods and apparatuses, and it is. especially adapted for the removal of the oily viscous film which stubbornly adheres to the inner surfaces of the intricate and inaccessible structures like the double bottoms of maritime vessels. These tanks commonly used as storage place for the heavy and viscous fuel oils used by oil'burning vessels, and due to the location and thecramped quarters of such tanks a thorough cleaning thereof is an extremely costly and slow undertaking. When repairs involving hot work like riveting and welding have to be done inside a double bottom tank, a thorough cleaning and gas freeing of the tank is required sothat the work may be undertaken in perfect safety and without any danger of explosion. Also when a double bottom tank is changed to carry freshwater instead of fuel oil, or when deep and cargo tanks are changed from fuel oil to gasoline, palm oil or other refined product every vestige of the viscous oil film which stubbornly clings to the metal surfaces in the tanks, has to be removed before the change can take place. I

Now however I have discovered that such cleaning may be done in a more economical and efficient manner and also in a much shorter time, by means of creating a fume laden steam and air circulation throughout the entire tank to be cleaned, and

5 inside the tank.

I use for my purpose any suitable fume generating solvent like carbon tetrachloride, kerosene et cetera in connection with my preferred apparatus, which employs steam as the circulating carrier, which is repeatedly circulated around the different inner tank surfaces andstructures In passing such surfaces the steam will continuously tend to condense together with the fume, whereupon the fume will combine with the oil film and form a light flowing liquid which readily falls to the bottom of the tank from which it is afterwards removed or pumped, and the tank is left in a skin clean condition and every remote nook and cranny has been reached and cleaned."

I claim as part of my invention not only the apparatus employed, but I also claim the different steps taken as a method and as a part of my invention. M

' In the drawing:

Figure 1 shows my preferred apparatus located in the wake'of the lightening holes of the frames in the double bottom of an oil burning vessel.

Figure 2 shows the details of construction of my preferred apparatus-on an enlarged scale.

Figure 3 represents a cross section of one frame space of the double bottom and shows the general construction thereof and also the location therein of my preferred apparatus.

I In the drawing where like reference characters denote corresponding parts, I denotes the ship, the double bottom tank 2 of which is shown being cleaned by my fume circulating process.

The double bottom tank 2 is divided into a series of frame spaces by the frames 3, which usually are spaced from two to three feet apart. and each frame space is further divided into three pockets by the lateral bulkheads 4. The division plates which form the honey-combed double bottom structure are provided with the centrally located my preferred fume circulating devices I are.

placed, all as shown on the drawing.

Each of these devices comprises a flexible hose 8, to the end of which'the circulating fluid jet pump 9, preferably steam driven, is attached.

The circulating pump 9 comprises the steam jacket III, which is provided with the steam inlet 1 I and into the threaded ends of which the pipes l2 and I3 are screwed. The longer pipe I3 is'at one end provided with the solvent inlet I8, and it is to be noted that the other end of this pipe is provided with a tapered end, registering closely with the adjacent tapered end of the pipe l2, so as to form a narrow annular opening, which constitutes the steam jet nozzle from the high pressure steam jacket.

The high pressure steam, which is preferred for the operation of the jet circulating pump is furnished through the steam line M, which is provided with the control valve [5 in the conventional manner. The conduit l6, through which the fume forming solventis pumped into the pipe I3, is adapted to be connected to a conveniently placed solventcontaine-r not shown on the draw- The temporary manhole covers l1, preferably a couple of bags of saw dust, are shown stuffed around the flexible hose conduits I land It in such a manner that the manholes [9 are substantially plugged up so as to prevent the steam jacket induces a high velocity air stream through the hose lines I, and the fume forming solvent 2. is blown into a spray as shown diagrammatically in the Figure 2 of the drawing. The spray II in entering and through the high pressure steam jet 2| is still further atomized and a fume laden steam cloud issues from each of the circulating pumps 9. These clouds are moving rapidly against each other, and in meeting the clouds naturally will broom out laterally and flll the several frame spaces, and the powerful air suction at the outer ends of the double bottom tank will induce a circulatingdlow towards the ends of the tank. The resulting circulation is diagrammatically illustrated by the dotted lines 22 in Figure 1 of the drawing.

In passing through the several openings of the frame plates and in moving against said plates the steam clouds will still further broom out laterally and be distributed eflectively over all the inner surfaces of the tank structure, and the steam in contacting the surfaces will tend to condense thereon and the fume laden condensate deposited on the surfaces will effectively dissolve the viscous oil film which adheres to the metal surfaces and drip to the bottom of the 'tank.

The fume circulation should preferably be maintained for a period of from one to two hours depending upon the condition of the tank. After a sufiicient circulation has been maintained in the tank, the steam and solvent supplies are cut oil and the manhole covers are removed, and the material precipitated to the tank bottom is preferably removed by a process and device similar to those shown in my pending application, Serial Number 30,434, by which the resulting sludge is removed by the ship pumps.

Iamnot limitingmyclaimsforinventicntothe apparatus shown. as it 'is obvious that modifications and alterations may be made in the adaptation of my device without departing from the scope and spirit of my invention.

I claim:

l. Themethodofcleanin'ganoilstorage tank, characterised by placing an extended pipe line inside the tank to be cleaned, injecting a high pressure steamjetintothepipeiinesoastosucka high velocity air stream therethrough, injecting a solvent for oil into the air stream and causing said solvent to be suspended in the air stream when it enters the steam jet in a spray formation, further atomizing the spray by means of the steam jet force and causing the steam cloud issuing from the pipe line to broom out laterally and repeatedly circulating the fume laden steam cloud through the pipe line so as to substantially reach all parts of the tank by said fume circulation.

2. The method oi cleaning double bottom tanks on board maritime vessels, comprising the placing of a pair of oppositely directed extended pipe lines in the wake of a row of lightening holes in the tank to be cleaned, injecting a high pressure steam jet in the direction of the circulating flow into each of the lines, injecting a solvent for oil so as to cause fume laden steam clouds to issue from said lines and to impinge one upon the other with sufficient velocity to cause a lateral brooming out of the clouds and repeatedly circulating the resulting steam laden atmosphere through the extended pipellnessoastosubstantiallyreachall parts of the inner double bottom structure by said the wake of a row of lightening holes, atomizing steam jets at the discharge ends of said lines, means for admitting a solvent for oilinto said lines and a suction intake to each of said lines locatedinthetankremotelyfromthedischarge ends of said lines. 

